The present invention relates to braking mechanisms for empty nail cartridge of nail guns and also relates to nail pushers which are slidablely placed in the nail cartridge, and particularly to a pushing arm pivotablely disposed on the nail pusher to punch a nail and brake a securing slide rod.
Braking mechanisms for empty nail cartridge of nail guns, also called punching-stop mechanisms for empty nail cartridge, are used for automatically detecting an empty state of the nail cartridge and the punch hole when the nail cartridge and punch hole runs out of nails. At the same time, the trigger can not be pulled and can not be driven to hit nail, so as to remind the user to reload the nails.
A conventional braking mechanism for empty nail cartridge, as disclosed in TW patent No.321044, utilizes a fixed braking unit extending from a lateral of a nail pusher of a nail cartridge. The nail pusher has a pushing claw for pushing aligned nails in sequence. After the last nail in the nail cartridge is hit, the nail pusher may travel a distance about a thickness of the nail towards the punch hole to stop the movement of the securing slide rod, so that the nail gun can be braked to hit nail and therefore remind the user to reload the nail cartridge. The conventional nail gun employs the nail having thickness about 0.6-1.2 mm. After the last nail in the nail cartridge is hit, the nail pusher may only travel 0.6-1.2 mm towards the punch hole to restrict the securing slide rod. So the securing slide rod may lack blocking area from the nail pusher. If the user unaware that the nails are used up, and pushes the securing slide rod in force, the securing slide hole may break away from the braking unit and affect the yield rate of the brake of the empty nail cartridge.
Further, a braking unit for empty nail cartridge to stop a securing slide rod is disclosed in TW patent No.I283625. The braking unit is slideably disposed on a nail pusher towards a punch hole by resilient thrust force. The braking unit has an ear at a lateral side thereof to push the nail. The nail pusher and the ear can push the nails into the punch hole by sequence. When the last nail in the nail cartridge is hit, the ear can move into the punch hole to restrict movement of the securing slide rod, so that the nail gun can be braked to hit nail. However, the blocking area of the braking unit is also inadequate. When the ear is resiliently moved into the punch hole, and if the nail gun is abnormally operated, the punch rod may move into the punch hole, therefore the punch rod may interfere the ear to move out of the punch hole.
Nowadays, some modified braking methods for empty nail cartridge of the nail guns are disclosed, such as in TW patent No. M269156. A poke member is disposed on a nail pusher of a nail gun. The nail pusher also has a pushing claw for pushing aligned nails in sequence. A slot is defined at a lateral side of the nail pusher. A braking member is rotatably placed in the slot. The braking member can be poked by the poke member. After the last nail in punch hole is hit, the nail pusher and the poke member may together move towards the punch hole travel about the thickness of one nail. The braking member is obliquely rotated out of the nail cartridge pushed by the poke member and placed on movement path of the securing slide rod of the nail gun. The securing slide rod is therefore blocked by the braking member and nail gun is braked to hit nail, so as to remind the user to reload the nails. However, when the braking member is rotated out of the nail cartridge, the securing slide rod can only abut on the cross-sectional area of the braking member out of the nail cartridge. The braking member may be forced by the securing slide rod along oblique direction. The braking member may be easily pushed by the oblique force to move to positions out of the braking position to weaken the stability of the securing slide rod and affect the yield rate of the brake of the empty nail cartridge. Therefore, above drawbacks need to be improved.